I hate to sound like a naysayer, but I really don't expect to see a G5 PowerBook until next year.
When IBM is able to shrink the chips even more (.65nm) and get the heat and power consumption issues under control and Apple is able to concoct a reasonable and extremely compact cooling system.... THEN we''ll see a G5 PowerBook. THEN wait until Rev.B!
A dual-core G4 seems more likely, but not until the end of the year at least. Some new PowerBooks have historically been released in November. I've bought 2 PowerBook G4s in different Novembers.
When Apple releases a new hardware Rev. you can count on it to be around for 6 to 9 months before a new Rev. is released. Also, prices start dropping before pending hardware Revs. PowerBook prices are holding steady. That makes it unlikely we'll see a PowerBook Rev. for at least a month, maybe longer?
I'm hoping that the G4s in the pending PowerBooks bring back the L3 cache, as well a speeding up the FSB and RAM. Faster graphics and more VRAM would be great, too.
Another question: WHERE are the bigger 7200 rpm 2 1/2" hard drives? A 100GB x 7200 rpm drive would be extremely nice.